The Fine Art of Dating

An interested reader writes, “I’m curious: how do you tell how old the things you’re excavating really are?” (OK, truth be known, my interested readers seem to keep their questions to themselves, but I think if they were inclined to ask questions, that would be a good one to ask, so I’ll ask and answer it for them!)

Dating is always somewhat problematic. Ask any high schooler. But dating in an archaeological sense involves correlating as many different approaches as you have available. The first stop is the library. What happened in this neck of the woods according to recorded history? Of course, this recorded history can be (and often is) somewhat inaccurate, having been recorded by people with different agendas, perspectives, and observational skills. Nonetheless, some basics can be gleaned, along with a good deal of specific information. One may argue about the causes and benefits, but it’s pretty clear from historical record that the English Colonies in America rebelled against the English Crown in 1776 or thereabouts, and established an independent nation. Likewise, there are a large number of rebellions, wars, incursions, and destructions of cities that dot the landscape of the history of the Shephelah. These destructive events, while not so nice for the residents at the time, are a boon to archaeologists, because they tend to be associated with large amounts of evidence of occupation, and because they may be linked to one of these historical events, giving a fixed date for that layer. And the building practices of the ancients in the middle east work to our advantage: they would build the next city on top of the old, with the result that over the millennia, a layered cake of dirt 80 or more feet high has been built up, waiting for the archaeologist’s trowel to discover its secrets.

There are many problems with depending on recorded history as a complete source of information on a site, so we turn to other sources of information which are much more direct, although one step away from a direct measurement of dates. These sources of information are the stratigraphy and ceramics analysis. We’ll call these ‘layers & pots.’

Like rings of a tree, the layers of occupational debris laid down by the occupants of the city are, as a general rule, older as you dig deeper. Note that I say ‘as a general rule’, because these layers are sometimes disturbed by pits, tunnels and the like, which can put younger material below older material, but with care, these anomalies can be detected, and identification of the chronological relationship of these layers (a stratigraphy) can be developed.

Sometimes the change in stratigraphy is pronounced and widespread (often as a result of a major destruction), leading the archaeologist to pronounce a different ‘phase’ of occupation. These phases are usually labeled with Roman Numerals, starting with the most recent, and they refer to these phases like family friends: Lachish IV, Megiddo VII, and now… Zeitah III.

But I have begged the question of how the archaeologist knows that the change in stratigraphy is pronounced and widespread. This is done by the analysis of pottery.

Ceramic material is wonderful stuff. Used for well over 7500 years, clay has been formed into many useful shapes, from fine dinner china to rough pots for holding plants outside one’s house. Pottery was the Tupperware™ of the ancients. Fairly easy to manufacture, a ceramic vessel will outlive its creator, and the more finely crafted pieces often increase with value as they age. They can be made to be porous or nonporous, may be decorated before or after firing, and as general purpose or as specific as one desires. Pottery’s most wonderful attribute, though, is that it is impervious to fire. Having already been fired, a little baking in a burning city may discolor it, but all but the most intense fires leave it unscathed.

Pottery’s second attribute that is helpful to archaeologists is that it was made individually by artisans (i.e. not mass produced), and the styles, colors, shapes and techniques these artisans used changed slowly over the years. Just as an automobile aficionado can trace the lineage of a modern Ford back to the Model T, and give dates of manufacture just by looking at its shape, a good ceramicist can do the same with pottery. By correlating the pottery styles, shapes, color & texture of clay, hardness of firing, and so on with pottery from phases from other sites where the dating has been established fairly well, these pottery sherds have become a very accurate indicator of age.

Because there are fairly widespread regional changes in the character of occupation, dates are not given in terms of years, but in terms of ‘ages’. You’re familiar with the terms ‘Stone Age’, ‘Bronze Age’, ‘Iron Age’ and so forth. Roughly speaking, these ages refer to the material tools would generally be made from: flint, copper alloys, iron. Different areas of the world used these materials at different times, so that the Bronze Age in Europe is different than the Bronze Age in the Levant (the Middle East). Here is a chart of the time periods at our site:

Date Range	Period
1,0000,000-8,300 BCE	Paleolithic
8,300-5,500 BCE	Neolithic
4,500-3,500 BCE	Chalcolithic
3,500-1,200 BCE	Bronze
3,000-2,000 BCE	Early Bronze
2,000-1,550 BCE	Middle Bronze
1,550-1,200 BCE	Late Bronze
1,200-586 BCE	Iron
1,200-1,000 BCE	Iron I
1,000-586 BCE	Iron II
586-332 BCE	Persian
332-37 BCE	Hellenistic
37 BCE-500 CE	Roman
500-638 CE	Byzantine
650-Present	Islamic
650-950 CE	Early Islamic
650-750 CE	Umayyad
750-950 CE	Abbasid
950-1525 CE	Middle Islamic
950-1175 CE	Fatimid
1075-1275 CE	Crusader
1170-1291 CE	Ayyubid/Mamluk
1291-1516 CE	Mamluk
1525-Present	Late Islamic
1517-1925 CE	Ottoman
1517-1800 CE	Early Ottoman
1800-1925 CE	Late Ottoman
1917-Present	Modern

A good ceramicist (Barbara Johnson and Gabi Barkay are among the best in the world) is able to categorize a sherd to within one of these time periods within a few seconds examination, and sometimes they can place the date of manufacture to a 100 or even 10 year range, depending on the sherd. For instance, a particular form of storage jar was made for only 2 or 3 years just prior to 586 BC in Judah, and given a special seal on the handle that read, “Lamelech,” or roughly, “to the king.” Rims and handles are particularly identifiable, and are usually called ‘diagnostic.’

Most of the work on the excavation revolves around the identification of these sherds: each day buckets of pottery are washed, dried, analyzed, recorded and the readings are entered into the computer, and I generate reports telling the earliest, latest, predominant and overall pottery dates for each bucket. The square supervisors use those reports in their analysis of their square.

Wouldn’t it be nice, though, to have a more direct way of measuring dates? Would I have brought it up if there weren’t? I’ll talk about that in the next journal entry.

(In the ‘biz’, that’s called a cliff-hanger)